Optical film laminate used for continuous lamination to panel component

ABSTRACT

A method for continuously manufacturing an optical display device comprises feeding a continuous web of optical film laminate including a continuous web of releasable film that includes a conductive layer and an optical film sheet that includes a conductive layer formed on the releasable film, bending the releasable film at a peeling body located in close vicinity of a lamination position, collecting the releasable film and thereby peeling the optical film sheet from the optical film laminate, sending the optical film sheet to the lamination position, and laminating the optical film sheet with a panel member which is conveyed to the lamination position by a panel conveying channel which makes at least a double-storied structure with a portion of a collecting channel where the releasable film is collected, attenuating static electrification generated on the optical film sheet, and continuously laminating the optical film sheet with the panel member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of U.S. patentapplication Ser. No. 15/557,688 filed Sep. 12, 2017, which is a NationalPhase application of International Application No. PCT/JP2015/080979filed on Nov. 4, 2015, which claims the priority of Japanese PatentApplication No. 2015-060266, filed on Mar. 24, 2015, in the Japan PatentOffice, the entire contents of which are incorporated herein byreference.

TECHNICAL FIELD

The present invention relates to a continuous web of optical filmlaminate to be used in a method and an apparatus for continuouslymanufacturing optical display devices by laminating optical film sheetsto panel components (hereinafter referred as “RTP lamination method andapparatus”).

More in particular, in RTP lamination method and apparatus forcontinuously manufacturing optical display devices by laminating opticalfilm sheets via adhesive layer to panel components conveyed to apredetermined lamination position, when a carrier film which islaminated to an adhesive layer and configures a continuous web ofoptical film laminate is peeled from the adhesive layer, the peeledcarrier film is statically electrified by peeling, which in turn causesinductive electrification on the panel components being conveyed to thepredetermined lamination position. On the other hand, a surface of theadhesive layer peeled from the carrier film is also staticallyelectrified by peeling, and when the optical film sheets including theelectrified adhesive layer is conveyed to the predetermined laminationposition and laminated to the panel components, it also causes inductiveelectrification on the panel components.

The present invention relates to a continuous web of optical filmlaminate given with electrification-preventing function for promptlyattenuating static charge of the optical film sheets including thestatically electrified carrier film and adhesive layer, in order tosolve new technical problem found in RTP lamination method andapparatus.

BACKGROUND ART

It has been well known that static electricity of electrified opticaldisplay device can deteriorate or can even damage built-in electroniccomponents. For example, electronic components built in a liquid crystalpanel include field effect transistors such as TFT elements. In order toprevent electrostatic discharge damage of such electronic components,manufacturing of liquid crystal display devices is normally completedafter processes described in the following.

In general, a liquid crystal panel has a structure where a liquidcrystal layer is encapsulated between a color filer layer (CF substrate)and a transparent electrode layer (TFT substrate). A liquid crystaldisplay device is finished at least after a process of laminatingrectangularly-shaped polarizing film sheets to both surfaces of a liquidcrystal panel. At this process, in RTP lamination method and apparatuswhich is different from conventional sheet lamination (sheet-typelamination) method and apparatus, when a polarizing film sheet is peeledfrom a carrier film, static electrification is caused in the carrierfilm, and on the other hand, the polarizing film sheet including anadhesive layer which is simultaneously statically electrified by peelingis laminated to a liquid crystal panel while peeling off from thecarrier film.

Conventional lamination method and apparatus, in general, comprisessteps of preparing many optical film sheets and accumulating them in amagazine, feeding an optical film sheet one by one, peeling a releasablefilm sheet from a polarizing film sheet having an adhesive layer withthe releasable film sheet, and positioning and laminating aseparately-conveyed liquid crystal panel to the exposed adhesive layerof the polarizing film sheet, and since a liquid crystal panel islaminated at a predetermined lamination position to a polarizing filmsheet which is previously peeled and the peeled releasable film sheet isprocessed without approaching to the predetermined lamination position,the releasable film sheet does not affect to the liquid crystal panel tobe laminated to a polarizing film sheet even if it is staticallyelectrified by peeling.

Thus, a remaining problem is how to attenuate static charge of apolarizing film sheet including an adhesive layer statically electrifiedby peeling, before laminating to a liquid crystal panel. Variousattempts have been made to address the problem.

RTP lamination method and apparatus comprise a process of peeling apolarizing film sheet including an adhesive layer from a carrier filmand simultaneously laminating the polarizing film sheet including theadhesive layer to a liquid crystal panel. More in particular, in RTPlamination method and apparatus, since a liquid crystal panel isconveyed to a predetermined lamination position in close vicinity of apeeled carrier film where a polarizing film sheet including an adhesivelayer is laminated to the liquid crystal panel while being peeled fromthe carrier film, it is not possible to avoid effect of the carrier filmand the polarizing film sheet that are statically electrified bypeeling. Inductive electrification of a liquid crystal panel due tostatic electrification caused by peeling was not considered inconventional lamination method and apparatus and is clarified as a newtechnical problem to be solved only in RTP lamination method andapparatus.

That is, at least two problems need to be solved to prevent staticelectrification of a liquid crystal panel in RTP lamination method andapparatus. A first problem is to prevent inductive electrification of aliquid crystal panel induced by a carrier film, being conveyed in closevicinity of the carrier film which is statically electrified by peeling.A second problem is how to address inductive electrification of theliquid crystal panel caused when laminating thereto a polarizing filmsheet including an adhesive layer which is statically electrified whilepeeling from the carrier film. If it is addressed incompletely,electronic components built-in an inductively-electrified liquid crystalpanel may be damaged by static electricity, or even if not damaged,light leaking parts due to orientation disorder of liquid crystal may befound in an inspection process in a completed liquid crystal displaydevice, as seen in a photograph in FIG. 2. As a result, a transmissioninspection of a liquid crystal display device as a product becomesdifficult which in turn compromises continuous manufacturing of a liquidcrystal display device.

Various proposals have been made for conventional technical problems.For example, Patent Document 1 describes an optical film laminate whichcan restrict affect of static electricity caused by peeling. More inparticular, a conductive layer is provided on a surface for forming anadhesive layer of an optical film configuring an optical film laminate.Patent Document 2 also describes as that an inductive adhesive layer isformed on an optical film laminate. Further, Patent Document 3 describesas that inductivity is provided to a continuous web of optical film tobe used for example in a surface protection film sheet for protecting apolarizing film sheet used, after being laminated to a liquid crystalpanel configuring an optical film laminate, in a manufacturing processof an optical display device. Patent Document 4 describes as that staticelectrification of an optical film laminate caused by peeling from areleasable film is controlled by intervening a conductive layer formedwith sheet resistance of 10² Ω/sq or higher and 10⁶ Ω/sq or less in theoptical film laminate.

Patent Document 5 describes a lamination method and an apparatus forcontinuously manufacturing optical display devices by restricting staticelectricity caused by peeling in optical film sheets to be laminated topanel components. More in detail, Patent Document 5 relates to alamination method and an apparatus for continuously manufacturingoptical display devices with a continuous web of optical film laminateconfigured with a base film which corresponds to a carrier film and afunctional film which corresponds to an optical film, including thatfunctional film sheets are formed from a functional film, the functionalfilm sheets are peeled with a peeling means from a base film i.e. acarrier film of the continuous web of optical film laminate, and thefunctional film sheets are laminated to the panel components.

Patent Document 5 further describes a lamination method and an apparatusin which a peeling means is configured with a material positioned onfurther negative side (or further positive side) in triboelectric seriesthan a carrier film when a continuous web of carrier film is negatively(or positively) charged by peeling, so that static electricity generatedin functional film sheets when peeling from the continuous web ofcarrier film does not electrically damage electrical components built inpanel components when manufacturing optical display devices bylaminating the functional film sheets to the panel components. PatentDocument 5 describes as that static electric charge generated in acarrier film is controlled and thereby electric charge in functionalfilm sheets is restricted by selecting a material of a peeling meansaccording to a state of static electrification, i.e. degree of negative(or positive) charge, of the carrier film caused by peeling, which is,in short, that electric charge of the functional film sheets to bedirectly laminated to the panel components is restricted.

PRIOR ART DOCUMENTS

-   -   Patent Document 1: Japanese Laid-Open Patent Application No.        2001-318230A    -   Patent Document 2: Japanese Laid-Open Patent Application No.        2014-032360A    -   Patent Document 3: Japanese Patent No. 4701750B    -   Patent Document 4: Japanese Laid-Open Patent Application No.        2009-157363A    -   Patent Document 5: Japanese Laid-Open Patent Application No.        2012-224041A    -   Patent Document 6: Japanese Laid-Open Patent Application No.        2004-338379A    -   Patent Document 7: Japanese Laid-Open Patent Application No.        2014-113741A

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention

An aim of the present invention is to provide a continuous web ofoptical film laminate which may promptly attenuate staticelectrification caused by peeling in both of the optical film laminateand a releasable film in RTP lamination method and apparatus forcontinuously manufacturing optical display devices by laminating opticalfilm sheets to panel components.

More in particular, in a continuous web of optical film laminate, staticelectrification prevention function is provided to a carrier film foravoiding static charge of the carrier film influencing to panelcomponents, and static electrification prevention function is alsoprovided to optical film sheets to be laminated to the panel components,so that electric charge generated by peeling may be promptly attenuatedbefore laminating the statically electrified optical film sheets to thepanel components. The continuous web of optical film laminate may beused in RTP lamination method and apparatus as a continuous web ofoptical film laminate having static electrification prevention functionwith sheet resistance of at least 10¹² Ω/sq or less.

Means for Solving the Problem

The problem may be solved by a continuous web of optical film laminatefor using in RTP lamination method and apparatus, comprising acontinuous web of optical film with an adhesive layer formed on onesurface thereof to be laminated at least to panel components and acontinuous web of releasable film with a releasably treated layer formedon a surface thereof contacting with the adhesive layer, in which, theoptical film is provided with static electrification prevention functionon the adhesive layer side while the releasable film is provided withstatic electrification prevention function on each of sides to be peeledwhen laminated to panel components such that static electrificationprevention function is provided to the releasably treated layer side.

A first aspect of the present invention is a continuous web of opticalfilm laminate for using in continuous lamination to panel components,comprising a continuous web of optical film with an adhesive layerformed on one surface thereof to be laminated at least to the panelcomponents and a continuous web of releasable film with a releasablytreated layer formed on a surface contacting with the adhesive layer, inwhich a continuous web of first conductive layer is intervened betweenthe optical film and the adhesive layer and a continuous web of secondconductive layer is intervened between the releasable film and thereleasably treated layer.

In the first aspect of the present invention, the first conductive layerand the second conductive layer are formed with a material whichprovides static electrification prevention function such that sheetresistance of both the optical film with the first conductive layerintervened between the optical film and the adhesive layer and thereleasable film with the second conductive layer intervened between thereleasable film and the releasably treated layer may be at least 10¹²Ω/sq or less. The material which provides static electrificationprevention function is preferably one of ionic surface-active agentincluding cationic or anionic agent, conductive polymer, or metal oxideincluding tin oxide or antimony oxide.

A second aspect of the present invention is a continuous web of opticalfilm laminate for using in continuous lamination to panel components,comprising a continuous web of optical film with an adhesive layerformed on one surface thereof to be laminated at least to the panelcomponents and a continuous web of releasable film with a releasablytreated layer formed on a surface contacting with the adhesive layer, inwhich the optical film is intervened with a continuous web of conductivelayer between the adhesive layer, and the releasable film is providedwith conductive function.

In the second aspect of the present invention, the releasable film ispreferably formed such that sheet resistance thereof is at least 10¹²Ω/sq or less by kneading a material which provides staticelectrification prevention function into polyethylene terephthalate(PET) resin. Further, the material which provides static electrificationprevention function is preferably one of ionic surface-active agentincluding cationic or anionic agent, conductive polymer, or metal oxideincluding tin oxide or antimony oxide.

Further, a conductive layer formed on one of surfaces of an optical filmmay be formed such that sheet resistance of the optical film with theconductive layer intervening between the optical film and the adhesivelayer is at least 10¹² Ω/sq or less by using a material which providesstatic electrification prevention function, and, the material whichprovides static electrification prevention function is preferably one ofionic surface-active agent including cationic or anionic agent,conductive polymer, or metal oxide including tin oxide or antimonyoxide.

A third aspect of the present invention is a continuous web of opticalfilm laminate for using in continuous lamination to panel components,comprising a continuous web of optical film with a conductive adhesivelayer formed on one surface thereof to be laminated at least to thepanel components and a continuous web of releasable film with areleasably treated layer formed on a surface contacting with theconductive adhesive layer, in which the releasable film is intervenedwith a conductive layer between the releasably treated layer.

In the third aspect of the present invention, the conductive adhesivelayer formed on one of surfaces of an optical film is preferably formedsuch that sheet resistance of the optical film including the conductiveadhesive layer is at least 10¹² Ω/sq or less by kneading a materialwhich provides static electrification prevention function into acrylicadhesive layer, and the material which provides static electrificationprevention function is preferably one of ionic surface-active agentincluding cationic or anionic agent, conductive polymer, or metal oxideincluding tin oxide or antimony oxide.

Further, a conductive layer configuring the releasable film may beformed with a material which provides static electrification preventionfunction such that sheet resistance of the releasable film with theconductive layer intervening between the releasably treated layer is atleast 10¹² Ω/sq or less, and the material which provides staticelectrification prevention function is preferably one of ionicsurface-active agent including cationic or anionic agent, conductivepolymer, or metal oxide including tin oxide or antimony oxide.

A fourth aspect of the present invention is a continuous web of opticalfilm laminate for using in continuous lamination to panel components,comprising a continuous web of optical film with a conductive adhesivelayer formed on one surface thereof to be laminated at least to thepanel components and a continuous web of releasable film with areleasably treated layer formed on a surface contacting with theconductive adhesive layer, in which the releasable film is provided withconductive function.

In the fourth aspect of the present invention, the conductive adhesivelayer formed on one of surfaces of an optical film is preferably formedsuch that sheet resistance of the optical film including the conductiveadhesive layer is at least 10¹² Ω/sq or less by kneading a materialwhich provides static electrification prevention function into acrylicadhesive layer, and the material which provides static electrificationprevention function is preferably one of ionic surface-active agentincluding cationic or anionic agent, conductive polymer, or metal oxideincluding tin oxide or antimony oxide.

In the fourth aspect of the present invention, the releasable filmconfiguring a continuous web of optical film laminate may be formed suchthat sheet resistance thereof is at least 10¹² Ω/sq or less by kneadinga material which provides static electrification prevention functioninto polyethylene terephthalate (PET) resin, and the material whichprovides static electrification prevention function is preferably one ofionic surface-active agent including cationic or anionic agent,conductive polymer, or metal oxide including tin oxide or antimonyoxide.

In the first to the fourth aspect of the present invention, thecontinuous web of optical film laminate may be wound as a roll. Also, awound roll may be slit to a width corresponding to a long side or ashort side of a panel component to be used in RTP lamination apparatus,and may be wound again to form feeding rolls for the RTP laminationapparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 (a) and FIG. 1 (b) are schematic diagrams showing an entire RTPlamination apparatus and an enlarged partial view thereof.

FIG. 2 is a photograph showing light leaking phenomenon of an opticaldisplay device (a liquid crystal panel).

FIG. 3 (a), FIG. 3 (b) and FIG. 3 (c) are schematic diagrams showingorientation disorder of liquid crystal caused by inductiveelectrification of an optical display device (a liquid crystal panel).

FIG. 4 (a) and FIG. 1 (b) are schematic diagrams explaining contactbetween a peeling body and a carrier film.

FIG. 5 shows structures of examples 1 to 5 and comparative examples 1 to5 for testing.

FIG. 6 shows test results including sheet resistance of a conductivefunction given layer on optical film side and releasable film side.

FIG. 7 is a diagram showing RTP lamination apparatus using laminationdrums of vacuum-suction structure.

BEST MODE FOR IMPLEMENTING THE INVENTION

FIG. 1 (a) is a schematic diagram showing an entire RTP laminationapparatus. In the RTP lamination apparatus 10, a continuous web ofoptical film laminate 1 is wound on a feeding roller R1. The opticalfilm laminate 1 comprises a carrier film 2 having a width correspondingat least to a size (a long side or a short side) of a panel component 5and a plurality of optical film sheets 3 continuously supported on anadhesive layer 4 formed on one of surfaces of the carrier film 2. Theoptical film sheets 3 are formed on a film sheet including the adhesivelayer 4 by forming slit lines reaching to a surface of the carrier film2 in an optical film laminated via the adhesive layer 4 to the carrierfilm 2 with intervals corresponding to a size (a short side or a longside) of the panel component 5.

The RTP lamination apparatus 10 comprises a film feeding apparatus 80consisting of up-stream rollers 81 for feeding the optical film laminate1 from the feed roller R1 and down-stream rollers 82 for winding acontinuous web of carrier film 2 peeled from the optical film laminate 1on a winding roller R2. Such configuration allows for conveying thecontinuous web of optical film laminate 1 without slacking toward apredetermined lamination position 100, and peeling optical film sheets 3including an adhesive layer 4 from the carrier film 2 of the continuousweb of optical film laminate 1 by a peeling body 60 having a tip-end 61arranged in vicinity of the predetermined lamination position 100. Whilepeeling the optical film sheets 3, the continuous web of carrier film 2is collected on the winding roller R2 via a conveying channel 110 forthe continuous web of carrier film 2.

As shown for example in FIG. 1 (b), the peeling body 60 is rectangularhaving a width at least of the continuous web of optical film laminate 1and a structure of wedge-shaped cross section with the tip-end 61 as aleading end may be assumed. Normally, the tip-end 61 configuring theleading end is arranged at a position in vicinity of the predeterminedlamination position 100, and the peeling body 60 is arranged as slopedimmediately below a conveying channel 310 of panel components 5. Theconveying channel 110 of the continuous web of carrier film 2 which isturned back at the tip-end 61 is normally positioned as a double-storiedstructure with the conveying channel 310 of the panel components 5.

In the RTP lamination apparatus, the panel components 5 are conveyed tothe predetermined lamination position, for example along the conveyingchannel 310 from a predetermined waiting position 300, as correspondingto the optical film sheets 3 including the adhesive layer 4 beingconveyed to the predetermined lamination position 100. At thepredetermined lamination position 100, a lamination apparatus 50including a lamination roller 51 laminates the optical film sheets 3 toone of surfaces of the conveyed panel components 5 via the adhesivelayer 4.

In manufacturing optical display device 6, since a panel component 5configuring the optical display device 6 normally has electroniccomponents such as Thin Film Transistor (TFT) built therein, staticelectrification prevention cannot be neglected in view of avoidingelectrostatic discharge damage. As already described in Patent Document5, prevention means for static electrification caused by peeling, i.e.for static electricity generated by peeling optical film sheets 3including an adhesive layer 4 laminated to the panel components 5 from acarrier film 2, is only one example. As shown in a schematic diagram ofFIG. 1 (a), for example, static electrical charge generated by peelingfrom the carrier film 2 in the optical film sheets 3 including theadhesive layer 4 may be restricted and controlled by using aself-discharging static eliminator 400 and/or an ionizer 410, or using acontinuous web of optical film laminate which has conductive function asdisclosed in Patent Document 4.

Nevertheless, as seen in the photograph of FIG. 2, light leaking partsare created in the optical display device 6 due to orientation disorderof liquid crystal. As a result, transmission inspection of the opticaldisplay device 6 as a product becomes impossible and continuousmanufacturing of the optical display device 6 is impaired.

When causes of the above are considered, it is found as that staticelectrification prevention by using the ionizer 410 in RTP laminationapparatus 10 is incomplete, because the statically electrified opticalfilm sheets 3 are immediately laminated to the panel components 5without sufficient static elimination after peeling from the carrierfilm 2. For a continuous web of optical film laminate which hasconductive function, sheet resistance of a conductive layer should be10⁶ Ω/sq or less, but such optical film laminate is too expensive whenmaterial cost is considered and is not realistic as a means for staticelectrification prevention.

The present invention has a feature that optical film sheets configuringa continuous web of optical film laminate and a conductive layerincluded in a carrier film are both formed on a peeling surface side andthat static electrical charge generated by peeling may be surelyattenuated even if sheet resistance is not reduced to 10⁶ Ω/sq or less.In that case, forming position of both conductive layer is important, asstatic electrification prevention function may not be exerted if theconductive layer is formed on a surface opposite to the peeling surface.Normally, it is preferable that an optical film laminate has amulti-layered structure in which a continuous web of protection filmmade from triacetylcellose (TAC) resin, acrylic resin or cyclo-olefinresin is laminated to at least one of surfaces of a continuous web ofpolarizer made from polyvinyl alcohol (PVA) resin, and that a releasablefilm is made from polyethylene terephthalate (PET) resin.

A continuous web of carrier film 2 is statically electrified by peelingfrom optical film sheets 3. The carrier film 2 statically electrified bypeeling is conveyed to a winding roller R2 via a conveying channel 110and collected. As seen in FIG. 1 (a) or (b), panel components 5 are, forexample, conveyed toward a predetermined lamination position 100 along aconveying channel 310 in an opposite direction in vicinity of thecarrier film 2 which is conveyed to be collected.

At that time, inductive electrification is caused in the panelcomponents 5 by the carrier film 2 as being collected, which affectselectronic components built in the panel components 5, and then lightleaking parts are created in optical display device 6 which ismanufactured by laminating the optical film sheets 3 to the panelcomponents 5, as shown in FIG. 2. This not only makes it difficult todetect defects with transmission inspection of the optical displaydevice 6 continuously manufactured by laminating the optical film sheets3 to the panel components 5, but also may be a cause of electrostaticdischarge damage of electronic components built in the panel components5 before laminating the optical film sheets 3. In order to avoid suchevent, static electrical charge in a continuous web of carrier film 2generated by peeling from optical film sheets 3 need to be controlledbelow a certain potential.

FIG. 4 (a) is a schematic diagram showing a state of staticelectrification when a continuous web of optical film laminate 1 ispeeled by a peeling body 60 into optical film sheets 3 and a continuousweb of carrier film 2. As shown in FIG. 4 (a), the optical film sheets 3including an adhesive layer 4 are peeled from the carrier film 2, and,while statically electrified by peeling, are laminated to one ofsurfaces of the panel components 5 conveyed to a predeterminedlamination position.

In the optical display device 6 manufactured under such state, inductiveelectrification is caused in the panel components 5 before reaching tothe predetermined lamination position by the carrier film 2 staticallyelectrified by peeling. Further, the optical film sheets 3 including theadhesive layer 4 are peeled from the carrier film 2 and, while beingstatically electrified by peeling, are laminated to one of surface ofthe panel components 5 conveyed to the predetermined lamination position100. Either inductive electrification from the carrier film 2 orinductive electrification caused by laminating the staticallyelectrified optical film sheets 3 including the adhesive layer 4inevitably leads to a risk of deteriorating and electrostaticallydamaging electronic components built in the optical display device 6,which is considered as technically not avoidable.

For example, when a mechanism of orientation disorder of liquid crystalgenerated in an optical display device caused by inductiveelectrification as shown in FIG. 3 (a) to FIG. 3 (c) is considered for acase where the optical display device 6 is a liquid crystal panel, it isfound as follows. That is, the panel components 5 shown in FIG. 3 (a) toFIG. 3 (c) are objected for liquid crystal panels 5 in which a liquidcrystal layer 503 is sealed in between a color filter substrate (CFsubstrate) 501 on viewing side and a TFT substrate 502 on non-viewingside. For example, as shown in FIG. 3 (b), in the panel components 5which pass below a continuous web of carrier film 2 conveyed toward apredetermined lamination position 100 with negative charge generated bystatic electrification by peeling, static charge is polarized on bothsurfaces thereof due to inductive electrification.

More in particular, as seen in FIG. 3 (b), a surface of the CF substrate501 closer to the carrier film 2 is positively charged and a bottomsurface of the TFT substrate 502 is negatively charged. As a result, abottom surface of the CF substrate 501 which forms a top surface of theliquid crystal layer 502 is negatively charged and a top surface of theTFT substrate 502 which forms a bottom surface of the liquid crystallayer 502 is positively charged, and then the liquid crystal layer 503is activated by the potential difference. Since light passes where theliquid crystal layer 503 is activated, a surface of the panel components5 looks like white-spotted.

Inductive electrification caused by laminating statically electrifiedoptical film sheets 3 including an adhesive layer 4 may be explained asa same phenomenon. A problem is that, if the panel components 5 arestatically charged over the upper limit of electrostatic charge,transistors in closed state are statically charged which takes time toattenuate while the liquid crystal layer 503 is continued to beactivated due to potential difference, which in turn makes thewhite-spotted state shown in FIG. 2 continue. Thus, the technicalproblem to be solved by the present invention is to find a technicalmeans to promptly attenuate static electrification of the panelcomponents 5 so that the upper limit of electrostatic charge is notexceeded.

In RTP lamination device 10, it is difficult to provide that staticelectrification by peeling is not caused in a carrier film 2 peeled froma continuous web of optical film laminate 1. It is difficult to avoid acertain degree of inductive electrification in the panel components 5because, normally, a conveying channel 110 for collecting a carrier film2 which is statically electrified by peeling and a conveying channel 310of panel components 5 are closely arranged. It is also difficult toavoid inductive electrification in the panel components 5 becauseoptical film sheets 3 including an adhesive layer 4 which are staticallyelectrified by peeling from a carrier film 2 are laminated to the panelcomponents 5.

As shown in FIG. 4 (b), the inventors of the present invention havecreated, in order to address those problems, a continuous web of opticalfilm laminate 1 in which a carrier film 2 is provided with conductivefunction to so that static charge generated in the carrier film 2 bypeeling is promptly attenuated, and further optical film sheets 3including an adhesive layer 4 are provided with conductive function sothat static charge generated in the optical film sheets 3 by peeling ispromptly attenuated, and then have checked that light leakage in panelcomponents 5 is not caused at what degree of upper limit ofelectrostatic charge i.e. allowable electrostatic charge for Examples 1to 3 and Comparative Examples 1 and 2 shown in FIG. 5 in tests asfollows.

Test for Example 1 consisted of: a first step of preparing, as anoptical film, an optical film laminate (NPF-CMG1765CU) from Nitto DenkoCorporation which has a structure as a conductive layer being formed onone of surfaces of a polarizing film and a releasable film beinglaminated via an adhesive layer on the conductive layer; a second stepof peeling the releasable film from the prepared optical film laminateand forming an optical film laminate by laminating a releasable filmwith conductive function (MRF38CK(CT-EF)/38 μm PET film from MitsubishiPlastics Inc.) to an adhesive layer side of the exposed optical filmsuch that a conductive layer thereof is on the adhesive layer side; athird step of manufacturing a liquid crystal display device by peelingthe releasable film from the optical film laminate and laminating theoptical film including the adhesive layer to both surfaces of a panelcomponent (a liquid crystal cell) taken out from a liquid crystal TV(49UB8300-CG) from LG Electronics; and a fourth step of placing theliquid crystal display device on a back light to visually checkorientation disorder of liquid crystal.

Sheet resistance of an optical film with a conductive layer interveningbetween the optical film and an adhesive layer and sheet resistance of areleasable film with a conductive layer intervening between releasablytreated layer to be peeled in the third step are both set at 10¹² Ω/sq,and then, Examples without orientation disorder of liquid crystal andwith orientation disorder which disappears within one minute areevaluated as ∘, and those with orientation disorder of liquid crystalwhich takes more than 1 minute are evaluated as x. Example 1 wasevaluated as ∘ as shown in FIG. 6.

Comparative Example 1 to be compared with Example 1 was similarlyevaluated through: a first step of preparing an optical film laminate inwhich a releasable film is formed in an adhesive layer, which does nothave a conductive layer i.e. a static electrification prevention layerbetween a polarizing film and the adhesive layer; a second step ofpeeling the releasable film and forming an optical film laminate bylaminating a releasable film (MRF38CK(CT-NS2)) without conductivefunction from Mitsubishi Plastics Inc. to the adhesive layer side of thepolarizing film; and similar steps as for Example 1. Comparative Example1 was not provided with a conductive layer on a side of the optical filmincluding the adhesive layer to be peeled or on a side of the releasablefilm, and it was evaluated as x as shown in FIG. 6.

Comparative Example 2 was similarly evaluated through: a step of formingan optical film laminate by laminating a releasable film withoutconductive function as in Comparative Example 1 to an adhesive layerside of an optical film after peeling a releasable film from an opticalfilm laminate from Nitto Denko Corporation with a structure as areleasable film is laminated via an adhesive layer to an optical filmhaving a conductive layer as in Example 1, i.e. an optical film withsheet resistance of 10¹² Ω/sq in which a conductive layer is intervenedbetween the optical film and an adhesive layer, and similar steps as forExample 1. Optical film of Comparative Example 2 to be laminated to bothsurfaces of a liquid crystal cell has a conductive layer, but areleasable film to be peeled is not provided with conductive function,and it was evaluated as x, as shown in FIG. 6, similar as forComparative Example 1.

Example 2 was formed with a method of the example 2 described in PatentDocument 6 as an optical film, and was different from Example 1 only inthat Example 2 uses an optical film having a conductive layer with sheetresistance set at 10⁸ Ω/sq which was intervened between a polarizingfilm and an adhesive layer. Sheet resistance of a releasable film to bepeeled in the third step was set at 10¹² Ω/sq, and Example 2 was testedthrough similar steps as for Example 1 and was evaluated as ∘ as shownin FIG. 6, similar as for Example 1.

Example 3 is an optical film prepared such that values of sheetresistance on the optical film side and that on a releasable film sideare reversed from those in Example 2. More in particular, an opticalfilm laminate was formed by laminating a releasable film, formed byappropriately mixing curing silicon resin (KS847H from Shin-EtsuChemicals Co., Ltd.) and polythiophene-containing conductive polymerresin (AS-D09E from Shin-Etsu Polymer Co., Ltd.) such that sheetresistance thereof is 10⁸ Ω/sq with a method disclosed in the example 1described in Patent Document 7, to an adhesive layer side of an opticalfilm with a conductive layer with sheet resistance set at 10¹² Ω/sq asin Example 1 between a polarizing film and an adhesive layer, andExample 3 was similarly evaluated as Example 1. Result was ∘ as shown inFIG. 6.

Further, as shown in FIG. 5, examples 4 or 5, and comparative examples 3to 5 are tested to check that light leakage in panel components 5 is notcaused at what degree of upper limit of electrostatic charge i.e.allowable electrostatic charge. Examples 4 or 5 consisting of an opticalfilm having an adhesive layer with conductive function formed thereonand comparative examples 3 to 5 to be compared with the examples 4 or 5were evaluated similarly as described in the above.

Example 4 was an optical film laminate formed by, as an optical film,laminating a releasable film formed in Example 3 i.e. a releasable filmformed by appropriately mixing curing silicon resin (KS847H fromShin-Etsu Chemicals Co., Ltd.) and polythiophene-containing conductivepolymer resin (AS-D09E from Shin-Etsu Polymer Co., Ltd.) such that sheetresistance thereof is 10⁸ Ω/sq with a method disclosed in the example 1described in Patent Document 7 to a polarizing film with sheetresistance of 10⁸ Ω/sq which has an adhesive layer with conductivefunction formed on one surface thereof by appropriately adjusting volumeof triethylsulfonium bis(trifluoromethanesulfonyl)imide (from TokyoChemical Industry Co., Ltd.) with a method of the example 14 describedin Patent Document 2, and Example 4 was similarly evaluated asExample 1. Result was ∘ as shown in FIG. 6.

Comparative example 3 to be compared with the example 4 was an opticalfilm laminate formed by laminating a releasable film similar to one inthe comparative example 3 i.e. a releasable film (MRF38CK(CT-NS2))without conductive function from Mitsubishi Plastics Inc. to an opticalfilm similar to one in the example 4 i.e. a polarizing film with sheetresistance of 10⁸ Ω/sq which has an adhesive layer with conductivefunction to one of surfaces of one of protection films, and Example 4was similarly evaluated as Example 1. Result was x, as shown in FIG. 6,similar as for Comparative Example 1 or 2.

Comparative Example 4 was an optical film similar to one in ComparativeExample 1 i.e. an optical film laminate formed by laminating areleasable film, formed by appropriately mixing curing silicon resin(KS847H from Shin-Etsu Chemicals Co., Ltd.) and polythiophene-containingconductive polymer resin (AS-D09E from Shin-Etsu Polymer Co., Ltd.) suchthat sheet resistance thereof is 10⁸ Ω/sq with a method disclosed in theexample 1 described in Patent Document 7, to an adhesive layer formed ona polarizing film without a conductive layer between the polarizing filmand the adhesive layer, and Comparative Example 4 was similarlyevaluated as Example 1. Result was x, as shown in FIG. 6, similar as forComparative Example 1, 2 or 3.

Example 5 was an optical film laminate formed by laminating a releasablefilm formed such that sheet resistance thereof is 10¹² Ω/sq as inExample 1 to a polarizing film formed with a similar method as inExample 4 i.e. a polarizing film with sheet resistance of 10¹² Ω/sqwhich has an adhesive layer with conductive function formed on onesurface thereof by appropriately adjusting volume of triethylsulfoniumbis(trifluoromethanesulfonyl)imide (from Tokyo Chemical Industry Co.,Ltd.) with a method of the example 14 described in Patent Document 2,and Example 5 was similarly evaluated as Example 1. Result was ∘ asshown in FIG. 6, similar as for Example 1 to 4.

Comparative Example 5 to be compared with Example 1 to 5 was an opticalfilm laminate formed by laminating a releasable film formed by coatingcuring silicon resin (KS847H from Shin-Etsu Chemicals Co., Ltd.) to asurface contacting with an adhesive layer of the releasable film andcoating polythiophene-containing conductive polymer resin (AS-D09E fromShin-Etsu Polymer Co., Ltd.) to a surface opposite to the surfacecontacting with the adhesive layer of the releasable film such thatsheet resistance thereof is 10⁸ Ω/sq with a method disclosed inParagraph [0130] of Patent Document 7 to an optical film having asimilar conductive layer as in Example 1 i.e. an adhesive layer side ofan optical film in which a releasable film is peeled from a polarizingfilm from Nitto Denko Corporation with a structure as that a conductivelayer is formed on one of surfaces of a polarizing film such that sheetresistance thereof is 10¹² Ω/sq and a releasable film is laminated viaan adhesive layer on the conductive layer, and Comparative Example 5 wassimilarly evaluated as Example 1. Result was x, as shown in FIG. 6,similar as for Comparative Example 1 to 4.

By the way, as shown in FIG. 1 (a) and FIG. 1 (b), although the presentinvention has been presented by using RTP lamination apparatus having apeeling body 60 with a structure of wedge-shaped cross section assumedtherefor being arranged in vicinity of a predetermined laminationposition 100, it is obvious that RTP lamination apparatus is not limitedas such.

For example, RTP lamination apparatus using lamination drums with vacuumsuction structure shown in FIG. 7 may be envisaged. In such RTPlamination apparatus, optical film sheets 3 are peeled from a peelingmember, and a surface of the optical film sheets 3 opposite to a surfacewhich an adhesive layer formed thereon is absorbed to lamination drums200 by vacuum suction. As such, the optical film sheets 3 are rolled tothe lamination drums 200 and conveyed to a predetermined laminationposition so as to overlap with panel components 5, where the opticalfilm sheets 3 are laminated such that the surface which the adhesivelayer being formed thereon is pressed against the panel components 5.

Although the present invention has been described for preferableembodiments, those skilled in the art may understand that variousmodifications may be made and elements may be replaced with equivalentswithout departing the scope of the present invention. Therefore, thepresent invention should not be limited to specific embodimentsdisclosed as the best mode of embodiments considered for implementingthe present invention, and it is intended that the present inventionencompasses all embodiments which belong to claims.

EXPLANATION OF NUMERICAL CHARACTERS

-   1: Optical film laminate-   2: Carrier film-   3: Optical film or Optical film sheet-   4: Adhesive layer-   5: Panel component-   6: Optical display device-   10: RTP apparatus-   50: Lamination apparatus-   60: Peeling body-   100: Predetermined lamination position-   110: Conveying channel of carrier film-   310: Conveying channel of panel component-   400: Self-discharging static eliminator-   410: Ionizer-   501: CF substrate-   502: TFT substrate-   503: Liquid crystal layer

The invention claimed is:
 1. A method for continuously manufacturing anoptical display device by, feeding a continuous web of optical filmlaminate including a continuous web of releasable film having a width atleast corresponding to a dimension of a panel member, and an opticalfilm sheet continuously supported by an adhesive layer formed on thereleasable film, bending the releasable film at a tip end forming afront end of a peeling body having a cross section of wedged shapewherein the tip end is configured at a position in close vicinity of apredetermined lamination position, collecting the releasable film andthereby peeling the optical film sheet with the adhesive layer from theoptical film laminate and sending the optical film sheet to thepredetermined lamination position, and laminating the optical film sheetby the adhesive layer with the panel member which is conveyed to thepredetermined lamination position by a panel conveying channel whichmakes at least a double-storied structure with a portion of a collectingchannel of the releasable film being collected, wherein, in the opticalfilm laminate, a first conductive layer is formed between the opticalfilm sheet and the adhesive layer formed on one of opposite surfaces ofthe optical film sheet, and a second conductive layer is formed betweena releasably treated layer formed on a releasable film surface opposingthe adhesive layer and the releasable film, the method including stepsof: feeding the optical film laminate without allowing loosening untilthe optical film sheet reaches the tip end of the peeling body, peelingthe optical film laminate at the tip end to be separated into theoptical film sheet supported by the adhesive layer being sent toward thepredetermined lamination position and the releasable film being bent atthe tip end to be collected so that at least a portion thereof makes adouble-storied structure with the panel conveying channel, forming aconductive layer from the optical film sheet through the releasable filmwhen lamination of the optical film sheet with the panel member by theadhesive layer is initiated at the predetermined lamination position, bypositioning the first conductive layer and the second conductive layeron a peeling surface side of the optical film sheet and the releasablefilm from the predetermined lamination position toward a conveyingdirection of the releasable film being bent at the tip end and conveyed,and attenuating static electrification generated on the peeling surfaceside of the optical film sheet when the optical film sheet is peeledwith the adhesive layer from the releasable film, and staticelectrification generated on the peeling surface side of the releasablefilm when the releasable film is peeled from the adhesive layer, bycontinuously conducting electricity from the predetermined laminationposition toward the conveying direction of the releasable film beingbent at the tip end and conveyed, and continuously laminating theoptical film sheet which static electrification is attenuated, with thepanel member at the predetermined lamination position.
 2. The method asdefined in claim 1, wherein the first conductive layer and the secondconductive layer of the optical film laminate are formed with a materialwhich provides static electrification prevention function, and sheetresistance of both the optical film sheet with the first conductivelayer intervening between the optical film and the adhesive layer andthe releasable film with the second conductive layer intervening betweenthe releasable film and the releasably treated layer is 10¹² Ω/sq orless.
 3. The method as defined in claim 2, wherein the material whichprovides static electrification prevention function is one of ionicsurface-active agent including cationic or anionic agent, conductivepolymer, or metal oxide including tin oxide or antimony oxide.
 4. Amethod for continuously manufacturing an optical display device by,feeding a continuous web of optical film laminate including a continuousweb of releasable film having a width at least corresponding to adimension of a panel member and an optical film sheet continuouslysupported by an adhesive layer formed on the releasable film, bendingthe releasable film at a tip end forming a front end of a peeling bodyhaving a cross section of wedged shape wherein the tip end is configuredat a position in close vicinity of a predetermined lamination position,collecting the releasable film and thereby peeling the optical filmsheet with the adhesive layer from the optical film laminate and sendingthe optical film sheet to the predetermined lamination position, andlaminating the optical film sheet by the adhesive layer with the panelmember which is conveyed to the predetermined lamination position by apanel conveying channel which makes at least a double-storied structurewith a portion of a collecting channel of the releasable film beingcollected, wherein, in the optical film laminate, a continuous web ofconductive layer is formed between the optical film sheet and theadhesive layer formed on one of opposite surfaces of the optical filmsheet, and the releasable film is provided with conductive function bymixing a material which provides static electrification preventionfunction, the method including steps of: feeding the optical filmlaminate without allowing loosening until the optical film sheet reachesthe tip end of the peeling body, peeling the optical film laminate atthe tip end to be separated into the optical film sheet supported by theadhesive layer being sent toward the predetermined lamination positionand the releasable film being bent at the tip end to be collected sothat at least a portion thereof makes a double-storied structure withthe panel conveying channel, forming a conductive layer from the opticalfilm sheet through the releasable film with the continuous web ofconductive layer and the releasable film provided with the conductivefunction when lamination of the optical film sheet with the panel memberby the adhesive layer is initiated at the predetermined laminationposition, by positioning the continuous web of conductive layer on apeeling surface side of the optical film sheet and the releasable filmfrom the predetermined lamination position toward a conveying directionof the releasable film being bent at the tip end and conveyed, andattenuating static electrification generated on the peeling surface sideof the optical film sheet when the optical film sheet is peeled with theadhesive layer from the releasable film, and static electrificationgenerated on the peeling surface side of the releasable film when thereleasable film is peeled from the adhesive layer, by continuouslyconducting electricity from the predetermined lamination position towardthe conveying direction of the releasable film being bent at the tip endand conveyed, and continuously laminating the optical film sheet whichstatic electrification is attenuated, with the panel member at thepredetermined lamination position.
 5. The method as defined in claim 4,wherein the continuous web of conductive layer is formed with a materialwhich provides static electrification prevention function, and sheetresistance of the optical film with the continuous web of conductivelayer intervening between the optical film and the adhesive layer is10¹² Ω/sq or less.
 6. The method as defined in claim 5, wherein thematerial which provides static electrification prevention function isone of ionic surface-active agent including cationic or anionic agent,conductive polymer, or metal oxide including tin oxide or antimonyoxide.
 7. The method as defined in claim 4, wherein the releasable filmis a polyethylene terephthalate (PET) resin film having sheet resistanceof 10¹² Ω/sq or less, provided with conductive function by mixing amaterial which provides static electrification prevention function. 8.The method as defined in claim 7, wherein the material which providesstatic electrification prevention function is one of ionicsurface-active agent including cationic or anionic agent, conductivepolymer, or metal oxide including tin oxide or antimony oxide.
 9. Amethod for continuously manufacturing an optical display device by,feeding a continuous web of optical film laminate including a continuousweb of releasable film having a width at least corresponding to adimension of a panel member and an optical film sheet continuouslysupported by an adhesive layer formed on the releasable film, bendingthe releasable film at a tip end forming a front end of a peeling bodyhaving a cross section of wedged shape wherein the tip end is configuredat a position in close vicinity of a predetermined lamination position,collecting the releasable film and thereby peeling the optical filmsheet with the adhesive layer from the optical film laminate and sendingthe optical film sheet to the predetermined lamination position, andlaminating the optical film sheet by the adhesive layer with the panelmember which is conveyed to the predetermined lamination position by apanel conveying channel which makes at least a double-storied structurewith a portion of a collecting channel of the releasable film beingcollected, wherein, in the optical film laminate, an adhesive layer isformed on one of opposite surfaces of the optical film sheet, theadhesive layer being a conductive adhesive layer, and a conductive layeris formed between a releasably treated layer formed on a releasable filmsurface opposing the conductive adhesive layer and the releasable film,the method including steps of: feeding the optical film laminate withoutallowing loosening until the optical film sheet reaches the tip end ofthe peeling body, peeling the optical film laminate at the tip end to beseparated into the optical film sheet supported by the conductiveadhesive layer being sent toward the predetermined lamination positionand the releasable film being bent at the tip end to be collected sothat at least a portion thereof makes a double-storied structure withthe panel conveying channel, forming a conductive layer from the opticalfilm sheet through the releasable film when lamination of the opticalfilm sheet with the panel member by the conductive adhesive layer isinitiated at the predetermined lamination position, by positioning theconductive adhesive layer and the conductive layer on a peeling surfaceside of the optical film sheet and the releasable film from thepredetermined lamination position toward a conveying direction of thereleasable film being bent at the tip end and conveyed, and attenuatingstatic electrification generated on the peeling surface side of theoptical film sheet when the optical film sheet is peeled with theconductive adhesive layer from the releasable film, and staticelectrification generated on the peeling surface side of the releasablefilm when the releasable film is peeled from the conductive adhesivelayer, by continuously conducting electricity from the predeterminedlamination position toward the conveying direction of the releasablefilm being bent at the tip end and conveyed, and continuously laminatingthe optical film sheet which static electrification is attenuated, withthe panel member at the predetermined lamination position.
 10. Themethod as defined in claim 9, wherein the conductive adhesive layer isprovided with conductive function by mixing a material which providesstatic electrification prevention function into acrylic adhesive layer,and sheet resistance of the optical film including the conductiveadhesive layer is 10¹² Ω/sq or less.
 11. The method as defined in claim10, wherein the material which provides static electrificationprevention function is one of ionic surface-active agent includingcationic or anionic agent, conductive polymer, or metal oxide includingtin oxide or antimony oxide.
 12. The method as defined in claim 9,wherein the conductive layer is formed with a material which providesstatic electrification prevention function, and sheet resistance of thereleasable film with the conductive layer intervening between thereleasable film and the releasably treated layer is 10¹² Ω/sq or less.13. The method as defined in claim 12, wherein the material whichprovides static electrification prevention function is one of ionicsurface-active agent including cationic or anionic agent, conductivepolymer, or metal oxide including tin oxide or antimony oxide.
 14. Amethod for continuously manufacturing an optical display device by,feeding a continuous web of optical film laminate including a continuousweb of releasable film having a width at least corresponding to adimension of a panel member and an optical film sheet continuouslysupported by an adhesive layer formed on the releasable film, bendingthe releasable film at a tip end forming a front end of a peeling bodyhaving a cross section of wedged shape wherein the tip end is configuredat a position in close vicinity of a predetermined lamination position,collecting the releasable film and thereby peeling the optical filmsheet with the adhesive layer from the optical film laminate and sendingthe optical film sheet to the predetermined lamination position, andlaminating the optical film sheet by the adhesive layer with the panelmember which is conveyed to the predetermined lamination position by apanel conveying channel which makes at least a double-storied structurewith a portion of a collecting channel of the releasable film beingcollected, wherein, in the optical film laminate, an adhesive layer isformed on one of opposite surfaces of the optical film sheet, theadhesive layer being a conductive adhesive layer, and the releasablefilm is provided with conductive function by mixing a material whichprovides static electrification prevention function, the methodincluding steps of: feeding the optical film laminate without allowingloosening until the optical film sheet reaches the tip end of thepeeling body, peeling the optical film laminate at the tip end to beseparated into the optical film sheet supported by the conductiveadhesive layer being sent toward the predetermined lamination positionand the releasable film being bent at the tip end to be collected sothat at least a portion thereof makes a double-storied structure withthe panel conveying channel, forming a conductive layer from the opticalfilm sheet through the releasable film when lamination of the opticalfilm sheet with the panel member by the conductive adhesive layer isinitiated at the predetermined lamination position, by positioning theconductive adhesive layer on a peeling surface side of the optical filmsheet and the releasable film from the predetermined lamination positiontoward a conveying direction of the releasable film being bent at thetip end and conveyed, and attenuating static electrification generatedon the peeling surface side of the optical film sheet when the opticalfilm sheet is peeled with the conductive adhesive layer from thereleasable film, and static electrification generated on the peelingsurface side of the releasable film when the releasable film is peeledfrom the conductive adhesive layer, by continuously conductingelectricity from the predetermined lamination position toward theconveying direction of the releasable film being bent at the tip end andconveyed, and continuously laminating the optical film sheet whichstatic electrification is attenuated, with the panel member at thepredetermined lamination position.
 15. The method as defined in claim14, wherein the conductive adhesive layer is provided with conductivefunction by mixing a material which provides static electrificationprevention function into acrylic adhesive layer, and sheet resistance ofthe optical film including the conductive adhesive layer is 10¹² Ω/sq orless.
 16. The method as defined in claim 15, wherein the material whichprovides static electrification prevention function is one of ionicsurface-active agent including cationic or anionic agent, conductivepolymer, or metal oxide including tin oxide or antimony oxide.
 17. Themethod as defined in claim 14, wherein the releasable film is apolyethylene terephthalate (PET) resin film having sheet resistance of10¹² Ω/sq or less, provided with conductive function by mixing amaterial which provides static electrification prevention function. 18.The method as defined in claim 17, wherein the material which providesstatic electrification prevention function is one of ionicsurface-active agent including cationic or anionic agent, conductivepolymer, or metal oxide including tin oxide or antimony oxide.